Castor



FIG. 1 is a side elevational view of a castor showing my new design withthe opposite side being a mirror image;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a top, front and side perspective view thereof.

The ornamental design for a castor, as shown and described.